/**
 * Copyright (c) 2008, Mu Dynamics.
 *  All rights reserved.
 *  
 *   Redistribution and use in source and binary forms, with or without modification, 
 *   are permitted provided that the following conditions are met:
 *   
 *  - Redistributions of source code must retain the above copyright notice, 
 *     this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice, 
 *     this list of conditions and the following disclaimer in the documentation and/or 
 *     other materials provided with the distribution.
 *  - Neither the name of the "Mu Dynamics" nor the names of its contributors may be used 
 *     to endorse  or promote products derived from this software without specific prior 
 *     written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.mu.jacob.core.renderer;

import java.io.File;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Properties;
import java.util.Map.Entry;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;

import com.mu.jacob.core.generator.GeneratorException;

/**
 * Velocity renderer
 * @author Adam Smyczek
 *
 */
public class VelocityRenderer extends AbstractRenderer {

	/* Velocity engine */
	private VelocityEngine velocityEngine;
	
	/* Velocity context */
	private VelocityContext velocityContext;

	/**
	 * @see com.mu.jacob.core.renderer.IRenderer#render(java.io.File)
	 */
	public String render(File templateFile) throws Exception {
		initEngine();
		Template template = getVelocityEngine().getTemplate(templateFile.getName());
		for (Entry<String, Object> e : getContextMap().entrySet()) {
	    	getVelocityContext().put(e.getKey(), e.getValue());
		}
		
		Writer writer = new StringWriter();
	    template.merge(getVelocityContext(), writer);
	    return writer.toString();
	}

	/**
	 * Initialize Velocity
	 */
	@Override
	protected void initEngine() {
		velocityEngine = new VelocityEngine();
		velocityContext = new VelocityContext();
		try {
			Properties properties = new Properties();
			properties.setProperty(VelocityEngine.FILE_RESOURCE_LOADER_PATH, getTemplateRoot().getAbsolutePath());
			properties.setProperty(VelocityEngine.FILE_RESOURCE_LOADER_CACHE, "false");
			properties.setProperty(VelocityEngine.INPUT_ENCODING, "UTF-8");
			properties.setProperty(VelocityEngine.RUNTIME_LOG_LOGSYSTEM_CLASS,
					"org.apache.velocity.runtime.log.SimpleLog4JLogSystem");
			properties.setProperty("runtime.log.logsystem.log4j.category", VelocityEngine.class.getName());
			getVelocityEngine().init(properties);
		} catch (Exception e) {
			throw new GeneratorException("Cannot initialize Velocity template engine!", e);
		}
	}

	/**
	 * @return velocity context
	 */
	protected final VelocityContext getVelocityContext() {
		return velocityContext;
	}

	/**
	 * @return velocity engine
	 */
	protected final VelocityEngine getVelocityEngine() {
		return velocityEngine;
	}

}
